Update namespaces to Common.Dto for DTO-related files

Refactored PlaceholderExtensions, DtoMappingProfile, and InvokeActionTests
to use the ReC.Application.Common.Dto namespace instead of
ReC.Application.Common.Behaviors.Action. Updated using directives and
namespaces to improve code organization for DTO-related logic.

src/ReC.Application/Common/Dto/DtoMappingProfile.cs

@@ -1,4 +1,3 @@
-using ReC.Application.Common.Behaviors.Action;
 using ReC.Domain.Views;
 
 namespace ReC.Application.Common.Dto;